/* sort_str.c -- reads in strings and sort them */
#include <stdio.h>
#include <string.h>
#define SIZE 81                        /* string length limit, including '\0' */
#define LIM 20                         /* maxium number of lines to be read */
#define HALT ""                        /* null string to stop input */
void stsrt(char *strings[], int num);  // string-sort function
char *s_gets(char *st, int n);

int main(void) {
  char input[LIM][SIZE]; /* array to store input */
  char *ptstr[LIM];      /* array of pointer variables */
  int ct = 0;            /* input count */
  int k;                 /* output count */

  printf("Input up to %d lines, I will sort them.\n", LIM);
  printf("To stop, press the Enter key at a line's start.\n");
  while (ct < LIM && s_gets(input[ct], SIZE) != NULL && input[ct][0] != '\0') {
    ptstr[ct] = input[ct];  // set ptrs to strings
    ct++;
  }

  stsrt(ptstr, ct);  // string sort
  puts("\nHere's the sorted list:\n");
  for (k = 0; k < ct; k++) puts(ptstr[k]);  // sorted pointers

  return 0;
}

// sorting function
void stsrt(char *strings[], int num) {
  char *temp;
  int top, seek;

  for (top = 0; top < num - 1; top++)
    for (seek = top + 1; seek < num; seek++)
      if (strcmp(strings[top], strings[seek]) > 0) {
        temp = strings[top];
        strings[top] = strings[seek];
        strings[seek] = temp;
      }
}

char *s_gets(char *st, int n) {
  char *ret_val;
  int i = 0;

  ret_val = fgets(st, n, stdin);
  if (ret_val) {
    while (st[i] != '\n' && st[i] != '\0') i++;
    if (st[i] == '\n')
      st[i] = '\0';
    else
      while (getchar() != '\n') continue;
  }
  return ret_val;
}